Multi-path radio frequency system using local oscillation signals with frequencies having non-integer multiple relationship that are generated from same reference oscillation signal and associated local oscillation signal generation method

Abstract

A multi-path radio frequency (RF) system includes a reference oscillation circuit, a local oscillation (LO) generator circuit, and mixer circuits. The reference oscillation circuit generates a reference oscillation signal. The LO generator circuit receives the reference oscillation signal, and generates LO signals according to the reference oscillation signal, where a frequency of the reference oscillation signal is a non-integer multiple of a frequency of at least one of the LO signals. The mixer circuits are located on different signal paths, respectively, and used to receive the LO signals from the LO generator circuit, respectively.

What is claimed is: 
     
         1 . A multi-path radio frequency (RF) system comprising:
 a reference oscillation circuit, configured to generate a reference oscillation signal;   a local oscillation (LO) generator circuit, configured to receive the reference oscillation signal, and generate a plurality of LO signals according to the reference oscillation signal, wherein a frequency of the reference oscillation signal is a non-integer multiple of a frequency of at least one of the plurality of LO signals; and   a plurality of mixer circuits, located on a plurality of signal paths, respectively, and configured to receive the plurality of LO signals from the LO generator circuit, respectively.   
     
     
         2 . The multi-path RF system of  claim 1 , wherein there is only a single mixer circuit located on each of the plurality of signal paths. 
     
     
         3 . The multi-path RF system of  claim 1 , wherein each of the plurality of LO signals has a 25% duty cycle. 
     
     
         4 . The multi-path RF system of  claim 1 , wherein the reference oscillation signal comprises a plurality of signals with a same frequency but different phases. 
     
     
         5 . The multi-path RF system of  claim 1 , wherein each of the plurality of LO signals comprises a plurality of signals with a same frequency but different phases. 
     
     
         6 . The multi-path RF system of  claim 1 , wherein at least one of the plurality of signal paths is a transmit (TX) path. 
     
     
         7 . The multi-path RF system of  claim 1 , wherein at least one of the plurality of signal paths is a receive (RX) path. 
     
     
         8 . The multi-path RF system of  claim 1 , wherein the LO generator circuit comprises:
 a frequency processing circuit, configured to generate a plurality of oscillation signals according to the reference oscillation signal, wherein the frequency of the reference oscillation signal is an integer multiple of a frequency of each of the plurality of oscillation signals, and the plurality of LO signals comprise a first LO signal that is selected from the plurality of oscillation signals; and   a frequency combination circuit, configured to combine at least a portion of the plurality of oscillation signals to generate a second LO signal included in the plurality of LO signals.   
     
     
         9 . The multi-path RF system of  claim 8 , wherein each of the plurality of oscillation signals comprises a plurality of signals with the same frequency but different phases. 
     
     
         10 . The multi-path RF system of  claim 8 , wherein each of the plurality of oscillation signals has a 25% duty cycle. 
     
     
         11 . The multi-path RF system of  claim 8 , wherein the plurality of oscillation signals comprise a first oscillation signal and a second oscillation signal that are combined at the frequency combination circuit, and the first oscillation signal and the second oscillation signal have a specific time delay therebetween. 
     
     
         12 . The multi-path RF system of  claim 11 , wherein the frequency processing circuit comprises:
 a frequency division circuit module, configured to perform frequency division upon the reference oscillation signal to generate a first frequency division signal and a second frequency division signal, and output the first frequency division signal and the second frequency division signal as the first oscillation signal and the second oscillation signal, respectively.   
     
     
         13 . The multi-path RF system of  claim 12 , wherein each of the first frequency division signal and the second frequency division signal comprises a plurality of signals with a same frequency but different phases. 
     
     
         14 . The multi-path RF system of  claim 11 , wherein the frequency processing circuit comprises:
 a frequency division circuit module, configured to perform frequency division upon the reference oscillation signal to generate a first frequency division signal and a second frequency division signal, and output the first frequency division signal as the first oscillation signal; and   a delay circuit, configured to receive the second frequency division signal, generate a delayed frequency division signal through delaying the second frequency division signal, and output the delayed frequency division signal as the second oscillation signal.   
     
     
         15 . The multi-path RF system of  claim 14 , wherein each of the first frequency division signal, the second frequency division signal, and the delayed frequency division signal comprises a plurality of signals with a same frequency but different phases. 
     
     
         16 . The multi-path RF system of  claim 11 , wherein a frequency of the first oscillation signal is not lower than a frequency of the second oscillation signal, and the specific time delay is equal to 
       
         
           
             
               
                 
                   ( 
                   
                     
                       T 
                       
                         F 
                         ⁢ 
                         A 
                       
                     
                     8 
                   
                   ) 
                 
                 × 
                 N 
               
               , 
             
           
         
       
       where T FA  is a period of the first oscillation signal, and N is an integer. 
     
     
         17 . The multi-path RF system of  claim 11 , wherein the frequency combination circuit generates the second LO signal by combining the first oscillation signal and the second oscillation signal, where a frequency of the second LO signal is equal to a sum of a frequency of the first oscillation signal and a frequency of the second oscillation signal. 
     
     
         18 . The multi-path RF system of  claim 8 , wherein the frequency combination circuit comprises combinational logics, transmission-gate logics, or a combination thereof. 
     
     
         19 . A local oscillation (LO) signal generation method comprising:
 receiving a reference oscillation signal generated from a reference oscillation circuit;   generating a plurality of LO signals according to the reference oscillation signal, where a frequency of the reference oscillation signal is a non-integer multiple of a frequency of at least one of the plurality of LO signals; and   outputting the plurality of LO signals to a plurality of mixer circuits that are located on a plurality of signal paths, respectively.   
     
     
         20 . The LO signal generation method of  claim 19 , wherein there is only a single mixer circuit located on each of the plurality of signal paths.